Conventionally, metal porous bodies made of metal such as nickel and an aluminum have been known (see Japanese Patent Laying-Open Nos. 8-170126 and 2013-60609). Further, as an application example of such a metal porous body, an electrode for generating plasma having carbon nanostructures formed on a surface of a metal porous body has been proposed (see Japanese Patent Laying-Open No. 2008-198469). Japanese Patent Laying-Open No. 2008-198469 describes that the carbon nanostructures are irregularly aligned on the surface of the metal porous body in order to implement an electrode capable of emitting electrons in multiple directions to generate plasma substantially uniformly with respect to an electrode substrate.
Further, conventionally, catalyst members having a catalyst metal such as platinum arranged on surfaces of carbon nanostructures such as carbon nanotubes have been known (see, for example, Japanese Patent Laying-Open No. 2007-126338). Japanese Patent Laying-Open No. 2007-126338 discloses arranging metal fine particles acting as a catalyst on the surfaces of the carbon nanostructures.